Protein Secretion in Legionella pneumophila
Emmy De Buck, Elke Lammertyn and Jozef Anné
from: Bacterial Secreted Proteins: Secretory Mechanisms and Role in Pathogenesis (Edited by: Karl Wooldridge). Caister Academic Press, U.K. (2009)
Legionella pneumophila is a Gram-negative facultative intracellular pathogen, which in its natural environment multiplies in protozoa. This bacterium can also cause a severe pneumonia in man, better known as Legionnaires' disease, following infection of alveolar macrophages. L. pneumophila enters its host cell by phagocytosis, creating a phagosome that does not fuse with lysosomes wherein bacteria can multiply. When nutrients are depleted, the bacteria enter the transmissive phase and express virulence proteins, resulting in lysis of host cells and the initiation of a new infection round. In each of these different stages of infection of host cells, virulence proteins need to be transported to their specific place of action. Several protein secretion systems have been identified in L. pneumophila and most of them were shown to play an important role in the virulence of this pathogen. An overview will be given of all secretion pathways identified so far and special attention will be paid to those secretion systems involved in virulence read more ...